Flow Machine

ABSTRACT

A flow machine includes two structural component parts that cooperate with one another by a bellows seal so that the bellows seal forms a medium barrier between two spaces of the flow machine which directly adjoin the two structural component parts. The flow machine is constructed as a gas turbine, and one space of the two spaces is a hot-gas space of a high-pressure stage of the gas turbine.

The invention is directed to a flow machine according to the preamble of claim 1.

A flow machine of the type mentioned above is known, e.g., from DE 1 751 075 A1. In the flow machine which is described in this document and which is constructed as a pressure exchanger, two structural component parts cooperate with one another by means of a bellows seal so that the bellows seal forms a medium barrier between two spaces in the flow machine which adjoin the two structural component parts.

It is the object of the invention to provide a novel solution for the use of a bellows seal in a flow machine.

This object is met by a flow machine according to claim 1. Further developments of the invention are defined in the dependent claims.

According to the invention, a flow machine has two structural component parts which cooperate with one another by a bellows seal so that the bellows seal forms a medium barrier between two spaces of the flow machine which directly adjoin the two structural component parts. The flow machine according to the invention is characterized in that the flow machine is constructed as a gas turbine, wherein one of the two spaces is a hot-gas space of a high-pressure stage of the gas turbine.

It was recognized by the inventors that the sealing area directly at the hot-gas space of a high-pressure stage of a gas turbine is extremely vulnerable to leakage because a levelness of sealing surfaces cannot be ensured during operation of the gas turbine due to an irregular circumferential distribution in the main gas flow. Further, once a leak has occurred, it has an exacerbating effect on the unevenness of the sealing surfaces so that the leakage effect increases. Further, there is the risk of overheating of sealing elements and, as a result, the loss of preloading or sealing force of the sealing elements.

Leakage can be reliably prevented through the use, according to the invention, of a bellows seal in this area.

According to an embodiment form of the invention, the other space of the two spaces is constructed as a cooling air space of the high-pressure stage of the gas turbine.

According to another embodiment form of the invention, the bellows seal has a first end portion by which it seals against a first structural component part of the two structural component parts and a second end portion by which it seals against a second structural component part of the two structural component parts, the first end portion being fastened to the first structural component part so that a deformation-tolerant connection is produced.

On the one hand, the inventive fastening of the bellows seal provides a reliable positional stability of the bellows seal and, on the other hand, permits a certain deformation of the connection of the bellows seal and first structural component part and, therefore, allows the bellows seal to be adapted to specific mechanical parameters while retaining a good sealing quality.

The first end portion is preferably welded, soldered, screwed, and/or cemented to the first structural component part.

According to yet another embodiment form of the invention, the second end portion seals against the second structural component part by area contact based only on axial preloading.

In this way, a connection is provided between the bellows seal and the second structural component part which tolerates movement but is nevertheless tight against media.

According to another embodiment form of the invention, the first end portion is constructed in the form of a flange which proceeds from an outer diameter of a fold part of the bellows seal and extends radially outward beyond the outer diameter of the fold part and rests on a radially extending sealing surface of the first structural component part, and the second end portion is constructed in the form of a flange which proceeds from the outer diameter of the fold part and extends radially inward in the opposite direction of the first end portion and rests on a radially extending sealing surface of the second structural component part.

Owing to this construction, the first end portion can be fixedly mounted at the first structural component part in a particularly simple and convenient manner. The second end portion lies inside the outer diameter of the fold and is therefore protected against damage.

According to another embodiment form of the invention, the first end portion has an axially extending connection portion which is connected to the fold part by a material bond so that an intermediate space is formed between the fold part and the sealing surface of the first structural component part.

The connection portion provides a lever arm so that the first end portion can deform to a certain extent in the area of the connection portion when the bellows seal is axially loaded and therefore provides deformation tolerance.

According to yet another embodiment form of the invention, a supporting surface or guide surface which extends axially in direction of the first structural component part adjoins the sealing surface of the second structural component part so that the supporting surface provides a radially inward support for the fold part.

Accordingly, a radial buckling of the fold part of the bellows seal and, therefore, impairment of preloading and of the sealing effect are prevented in a reliable manner when the bellows seal is pushed together axially. Further, the supporting surface provides an axial guide for the bellows seal.

According to yet another embodiment form of the invention, the sealing surface of the second structural component part, the supporting surface, and the sealing surface of the first structural component part extend in such a way that together they form a U-shaped circumferential receiving pocket for the fold part of the bellows seal.

In this way, the fold part of the bellows seal is received in such a way that it is protected even more reliably against damage and axial buckling.

According to another embodiment form of the invention, the first structural component part is formed by a stator blade carrier and/or a seal carrier of the high-pressure stage of the gas turbine.

Finally, a seal system according to the invention in the form of a bellows seal in the high-pressure stage of a gas turbine is used to compensate for large changes in the axial sealing gap, and the tightness of the two structural component parts from one space (hot-gas space) to the other space (cooling air space) is achieved through a defined preloading and delta p.

As an inventive solution, a deformation-tolerant connection of the two seal elements (bellows seal and stator blade carrier) is provided while retaining a good sealing quality. To this end, three possibilities are suggested: welding the bellows seal to the stator blade carrier, wherein the bellows geometry is designed in such a way that the structural component parts and the weld need only tolerate a minimum of stresses; soldering the bellows seal; and/or a screw/clamping connection between the bellows seal and stator blade carrier.

The invention will be described in more detail in the following with reference to a preferred embodiment form and the accompanying drawing.

FIG. 1 shows a schematic sectional view through a portion of a flow machine according to an embodiment form of the invention.

FIG. 1 is a schematic sectional view through a portion of a flow machine 1 according to an embodiment form of the invention which is constructed as a gas turbine.

The flow machine 1 has a first structural component part 10 and a second structural component part 20 which cooperate with one another by means of a bellows seal 30 such that the bellows seal 30 forms a medium barrier between a hot-gas space 40 of a high-pressure stage (not shown separately) of the flow machine 1, which hot-gas space 40 directly adjoins the two structural component parts 10, 20, and a cooling air space 50 of the high-pressure stage of the flow machine 1, which cooling air space 50 directly adjoins the two structural component parts 10, 20.

The first structural component part 10 is formed by a stator blade carrier of the high-pressure stage of the flow machine 1. The second structural component part 20 is formed, e.g., by a housing part of the high-pressure stage of the flow machine 1.

The bellows seal 30 is preferably produced from a heat-resistant, flexible metal or plastic.

The bellows seal 30 has a first end portion 31 by which it seals against the first structural component part 10 and a second end portion 32 by which it seals against the second structural component part 20.

The first end portion 31 is fastened to the first structural component part 10 by welding, soldering, screwing, or clamping so that a deformation-tolerant connection is produced. In the present embodiment form, the first end portion 31 is welded on or soldered on, for example.

To this end, the first end portion 31 is constructed in the form of a flange which proceeds from an outer diameter 33 a of a fold part 33 of the bellows seal 30 and extends radially outward beyond the outer diameter 33 a of the fold part 33 and rests on a radially extending sealing surface 11 of the first structural component part 10.

Further, the first end portion 31 has an axially extending connection portion 31 a which is joined to the fold part 33 by a material bond or is formed integral with the fold part 33 so that an intermediate space R1 is formed between the fold part 33 and the sealing surface 11 of the first structural component part 10.

When the bellows seal 30 is pushed together axially, the fold part 33 can deform into the intermediate space R1 by means of a deformation of the connection portion 31 a acting as a lever arm so that the connection provides deformation tolerance between the first end portion 31 and the first structural component part 10.

The second end portion 32 seals against the second structural component part 20 by area contact that is based solely on axial preloading in the direction of the second structural component part 20.

For this purpose, the second end portion 32 is constructed in the form of a flange which proceeds from the outer diameter 33 a of the fold part 33 and extends radially inward in the opposite direction of the first end portion 31 and rests on a radially extending sealing surface 21 of the second structural component part 20.

A supporting surface 22 which extends axially in direction of the first structural component part 10 adjoins the sealing surface 21 of the second structural component part 20 so that the supporting surface 22 provides a radially inward support for the fold part 33.

As can be seen from FIG. 1, the sealing surface 21 and the supporting surface 22 of the second structural component part 20 and the sealing surface 11 of the first structural component part 10 extend in such a way that together they form a U-shaped circumferential receiving pocket for the fold part 33 of the bellows seal 30 so that the fold part 33 is reliably protected against damage and axial buckling and is guided axially.

REFERENCE NUMERALS

-   1 flow machine -   10 structural component part -   11 sealing surface -   20 structural component part -   21 sealing surface -   22 supporting surface -   30 bellows seal -   31 end portion -   31 a connection portion -   32 end portion -   33 fold part -   33 a outer diameter -   40 hot-gas space -   50 cooling air space -   R1 intermediate space 

1. A flow machine constructed as a gas turbine comprising: a first structural component part; a second structural component part; and a bellows seal by which the first and second structural parts cooperate with one another by so that the bellows seal forms a medium barrier between two spaces of the flow machine that directly adjoin the two structural component parts, wherein one space of the two spaces is a hot-gas space of a high-pressure stage of the gas turbine.
 2. The flow machine according to claim 1, wherein the other space of the two spaces is a cooling air space of the high-pressure stage of the gas turbine.
 3. The flow machine according to claim 2, wherein the bellows seal comprises: a first end portion fastened to the first structural component part so that a deformation-tolerant connection is produced by which the bellows seal is sealed against the first structural component part; a second end portion by which the bellows is sealed against the second structural component part.
 4. The flow machine according to claim 3, wherein the second end portion seals against the second structural component part by area contact based only on axial preloading.
 5. The flow machine according to claim 4, wherein the first end portion is at least one of is welded, soldered, screwed, and cemented to the first structural component part.
 6. The flow machine according to claim 5, wherein the first end portion is configured as a first flange that proceeds from an outer diameter of a fold part of the bellows seal and extends radially outward beyond the outer diameter of the fold part and rests on a first radially extending sealing surface of the first structural component part, and the second end portion is configured as a second flange that proceeds from the outer diameter of the fold part and extends radially inward in an opposite direction to the first end portion and rests on a second radially extending sealing surface of the second structural component part.
 7. The flow machine according to claim 6, wherein the first end portion has an axially extending connection portion connected to the fold part by a material bond so that an intermediate space is formed between the fold part and the first sealing surface of the first structural component part.
 8. The flow machine according to claim 7, further comprising: a supporting surface that extends axially in a direction of the first structural component part that adjoins the second radially extending sealing surface to provide a radially inward support for the fold part.
 9. The flow machine according to claim 8, wherein the second radially extending sealing surface of the second structural component part, the supporting surface, and the sealing surface of the first structural component part each extend such that they form a receiving pocket for the fold part of the bellows seal.
 10. The flow machine according to claim 9, wherein the first structural component part is at least one of a stator blade carrier and a seal carrier of the high-pressure stage of the gas turbine.
 11. The flow machine according to claim 1, wherein the bellows seal comprises: a first end portion fastened to the first structural component part so that a deformation-tolerant connection is produced by which the bellows seal seals against the first structural component part, the first end portion; and a second end portion by which it seals against the second structural component part.
 12. The flow machine according to claim 3, wherein the first end portion is at least one of is welded, soldered, screwed, and cemented to the first structural component part.
 13. The flow machine according to claim 3, wherein the first end portion is configured as a first flange that proceeds from an outer diameter of a fold part of the bellows seal and extends radially outward beyond the outer diameter of the fold part and rests on a radially extending sealing surface of the first structural component part, and the second end portion is configured as a second flange that proceeds from the outer diameter of the fold part and extends radially inward in an opposite direction to the first end portion and rests on a radially extending sealing surface of the second structural component part.
 14. The flow machine according to claim 6, further comprising: a supporting surface that extends axially in a direction of the first structural component part that adjoins the second radially extending sealing surface to provide a radially inward support for the fold part.
 15. The flow machine according to claim 3, wherein the first structural component part is at least one of a stator blade carrier and a seal carrier of the high-pressure stage of the gas turbine. 